Plate cylinders for printing presses



Oct. 31, 1961 R. P. WILLARD 3,006,277

INTI

,ders. work had been completed, it was necessary to stop the .United States Patent Ofitice 3,006,277 Patented Oct. 31, 1961 3,006,277 PLATE CYLINDERS FOR PRINTING PRESSES Robert P. Willard, Durham, N.H., assignor to Kidder Press Company, Inc., Dover, N.H., a corporation of Delaware Filed May 15, 1959, Ser. No. 813,397 5 Claims. (Cl. 101-378) This invention relates to printing presses and more particularly to plate cylinders for use in a wide variety of presses, whether utilizing relief, planographic, or intaglio processes, or for black or multicolor work.

The general object of the invention is to provide a novel and improved plate cylinder assembly, including a basic core or supporting cylinder adapted to carry one or more interchangeable plate carrying sleeves, and thus to lend increased flexibility of operation and greater versatility to the press to which it is applied.

According to present practices, two methods are generally pursued in connection with repeat jobs, especially in multicolor work. In the case of smaller presses, the plate cylinders are made readily removable from the press, and at a point away from the press they are equipped with printing plates of various sizes, either of rubber, metal, or other suitable material, the plates for printing several different colors being mounted on separate cylinders, which plates are arranged to run in registry when the cylinders are replaced in the press.

Usually only one job is mounted on each set of cylinders. In the case of a multicolor job for a customer, the black printing plates would be mounted on one cylinder, the red printing plates on another, and the yellow printing plates, for example, on a third cylinder. Then after the run has been made, the cylinders for this particular job could be stored by themselves with the plates still mounted in registry in readiness for the next order for that job. Although there are certain advantages in this arrangement, for instance the ability to make re-runs without having to re-register the plates on the cylinder once they have been placed in registry the first time, this method does tie up or idle quite a few cylinders.

In the case of larger machines such as oil ink letterpress bread wrapper machines, it has not been found feasible to operate in this manner. In these presses, metal plates have been commonly employed, the plates being laboriously screwed onto the surfaces of the plate cylin- This of course meant that when any customers press, unscrew the plates for that particular job, screw fanother set of plates onto the cylinder, and register them -while the press was stopped. This is a time-consuming operation and not as eflicient even as that pursued in the case of the smaller presses where the platesare registered away from the press and it was only necessary to drop a complete cylinder in place to make a changeover to another job.

' bodiments, contemplates the provision of a novel printing plate cylinder assembly which is removable or displaceable from the press and which comprises'a basic cylinder structure provided with appropriate journaled ends, and upon which may be applied a multiplicity of sturdy rigid printing sleeves. These sleeves are of various lengths and adapted to be assembled upon the basic supporting cylinder structure to completely cover it from end to end. The sleeves and the basic cylinder are provided with cooperating registry devices for accurately locating them for even printing, and the sleeves are adapted to have their individual printing plates mounted on them outside of the press, preferably in a suitable registering machine. The sleeves must have completely unbroken surfaces upon which to mount the plates, and they must be capable of being independently slid longitudinally of the cylinder a slight distance for adjustment. It is also possible if desired to etch, engrave or otherwise fashion the design to be printed directly on the surface of the sleeve as opposed to attaching loose plates to the sleeve.

To attain these advantageous features, with the preservation of accuracy, the maintenance of strength and sturdiness of the parts, while at the same time keeping in mind the requisite simplicity of construction and operation of the mechanical features, presented quite a few problems; but they have been satisfactorily solved by the provisions of the present invention.

One of the principal expedients looking toward these ends, is the provision of pneumatic means for securing the printing sleeves to the basic cylinder member. The cylinder proper is cut away for about of its peripheral surface, and this segmental portion is replaced by an inflatable bag which, after the sleeves have been slid onto the cylinder and properly located, may be inflated and thus exert considerable pressure on the interior of the sleeve at one side thereof causing the inner surfaces of the sleeve to hug closely the remaining accurately formed 180 degrees of surface of the cylinder, and thus insure that the sleeves run concentrically and true,

Since the recessing of approximately a half portion of the surface of the cylinder would throw it into unbalance dynamically, compensating means are provided for lightening the solid half portion of the cylinder core.

Other objects and features of novelty will be apparent with the accompanying drawings in which one embodiment of the invention is illustrated by Way of example.

In the drawings:

FIGURE 1 is a view in perspective of a plate cylinder assembly employing the principles of the invention;

FIGURE 2 is a vertical transverse sectional view through the core portion of the plate cylinder in deflated condition and without the printing sleeves which it is designed to carry, such as Would be taken on line 22 of FIGURE 4 yet to be described;

FIGURE 3 is a similar sectional view, as taken on line 33 of FIGURE 1 and including one of the printing sleeves;

FIGURE 4 is a view in plan of a printing plate cylinder in process of the preparation, with one printing sleeve applied thereto; and

FIGURE 5 is a fragmentary vertical longitudinal sectional view taken on line 5-5 of FIGURE 3. v

In FIGURE 1 there is shown somewhat diagrammatically a printing plate cylinder assembly embodying the principles of the invention and to this member as a whole,

there is applied the general reference numeral 10. The assembly comprises an internal basic core or cylinder structure 12 having end journals 13 and 14 by which the assembly is mounted for rotation in a press.

"In the particular illustrated embodiment the supportv ing basic cylinder structure 12 carries three sectional printing sleeves indicated at 16, 17 and 18. These sleeves are interchangeable and a supply of various lengths may j be kept on hand for various jobs. In the present case the intermediate sleeve 17 is the longest, the left-hand sleeve 16 of an intermediate length, and the right-hand sleeve 18 quite narrow and adapted to carry the plate or plates of a relatively small job.

Suitably secured to the peripheral surfaces of the printing sleeves are the printing plates variously indicated at 20 in FIGURE 1, each sleeve carrying the plates for a particular printing job, such as advertisements, circulars, cartons, container wrappers, or the like.

Referring now especially to FIGURES 2 and 3 of the drawings it will be seen that the internal core or basic cylinder structure 12 is mounted upon an axial shaft member 21 which terminates in the journals 13 and 14. The supporting area of cylinder 12 is ground to an accurate and perfect cylindrical surface 23 for approximately 100 of its extent, but the remaining approximate half of the cylindrical surface is cut away or recessed leaving a cylindrical portion 24 of less radius than the accurately ground surface 23.

Adjacent the junction of the two portions 23 and 24 of the surface of the cylinder member 12 there may be provided a shouldered or stepped portion 25 and, as suggested in FIGURES 4 and of the drawings, the ends of the cylinder 12 may be provided with a semi-circular raised shoulder as indicated at 26.

Secured and sealed by suitable fastening means along the entire shoulder 25 and around the raised portion 26 at the ends of the cylinder, are the edges of an inflatable elastic and expansible member 30. This member 30 may be made of rubber, either natural or synthetic, and of suitable durability, and if desired suitably reinforced in order to strengthen its structure without impairing to any great extent its expansibility. While any suitable securing .means may be employed, the ones shown diagrammatically in the drawings comprise a series of screws or rivet elements 32 which, throughout the margins of the bag portion 30 or in certain selected portions such as the ends of the installation, may be provided with a series of washers suggested at 33. Any further precautions looking toward making the bag 30 airtight may be taken.

As shown at 35 in FIGURES l, 3 and 5, a suitable inflating valve is applied at one end of the assembly and is provided with a nipple leading into the interior of the bag portion 30. Any suitable supply of compressed air may be used such as diagrammatically. shown in FIGURE '5, where a hose 50 with a valved nozzle 51 leads from an air tank 52 supplied by-a compressor pump 55.

In order to maintain the cylinder in proper balance despite the cutting away of a peripheral portion for 180 of its circumference, metal may be removed from the otherhalf of the basic cylinder 12 by boring longitudinal openings 36 therethrough, or casting them therein.

In FIGURE 2 the basic supporting structure is shown in'deflated condition prior to the application of a printing sleeve thereto, while in FIGURE 3 one of the sleeves .16 has been, slid onto the basic cylinder structure 12,

being guided and located circumferentially by means of the keying set screw 40 which fits into the recess 41 in the cylinder 12. These screws are preferably of the recessed head Allen type and are not tightened but serve merely as locating or registering means, and the sleeves are thus free to move longitudinally of thecylinder whenever the air pressure is released.

When the sleeves are in place, compressed air is introduced through the valve 35 and the resulting expansion of the rubber bag portion 30 pulls the sleeves up against the accurately ground locating surface 23 of the basic cylinder 12, and suflicient air pressure is carried in the bag so that the printing pressure being used in the press run will be overcome and will not be able to push the sleeve back off of the locating surface 23. Of course, if it is desired at any time to move the sleeve slightly sideways for more accurate adjustment, the air can be let out of the bag 30 and the sleeve will thus be free to be moved.

The locating arrangement -4041 is provided to insure that the sleeves upon a given plate cylinder will line up with the same accuracy with respect to all of the other color locations with which the plates were originally mounted for the initial job when the plates were applied to the sleeve in the plate mounting machine remote from the press.

Of course, it should be mentioned that the plate cylinder sleeves 16, 17 and 18 and others of possibly different dimensions must all be sufliciently rigid so that they will not be distorted or brought out of round by the air pressure inside of the bag. If the sleeves were made too thin, the pressure of the air might cause the sleeve to assume an ovate configuration and poor printing would result.

Various changes and alterations may be made in the embodiments of the invention illustrated and described herein without departing from the scope of the invention as determined by the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:-

1. A printing plate cylinder system comprising a core member having journals at its ends for rotatablymounting it in its bearings in a printing press, said core mem ber having an accurately ground cylindrical surface for approximately of its periphery and centered on the axis of the core member, the remaining portion of said periphery being recessed from a cylindrical configuration, at least one readily removable and interchangeable rigid cylindrical printing sleeve surrounding said core member and having an internal cylindrical surface of the same curvature as said ground surface on said core member, expansible means disposed in the recessed portion of said core member and within said rigid sleeve, means for expanding said means at will for exerting substantially unilateral outward pressure upon the inner surface of said sleeve to cause a portion of said inner surface to conform exactly to the ground surfaces on said core member and thus to be positioned exactly concentric with said core member, and printing means carried by the outer surface of said sleeve.

2. The system as set forth in claim 1 in which said expansible means comprises a flexible-walled fluid-tight container occupying said approximately 180 recess only, and said expanding means comprising means for supplying said container with pressure fluid.

3. The system as set forth in claim 1 in which said expansible means comprises a flexible-walled expansible airtight container occupying said approximately 180 recess only, and said expanding means comprising means for inflating said container with compressed air to a pressure in excess of any force likely to displace the rigid sleeve during printing operation.

4. A printing plate cylinder system as set forth in claim 1, in which the depth of the recessed portion is less than the radius of the core member, and the ground surfaced portion is proportionately lightened to compensate for the removal of weight in providing the recess, by the provision of at least one bore hole extending longitudinally through said ground surfaced portion.

5. A printing plate cylinder comprising a core member having journals at its ends for rotatably mounting it in its hearings in a printing press, said core member having an accurately ground cylindrical surface for approximately'180 of its periphery and centered on theaxis of the core member, the remaining portion of said periphery being cut back from the cylindrical configuration of the radius of said ground surface; a sheet of flexible resilient material secured along itsside margins to said core member adjacent the boundary of the cylindrical portion and the cut-back portion, and its end margins secured around the cut-back portion of the core member, all portions of the sheet and its securing means being depressed below the projection of the ground cylindrical surface; a

valved nipple extending through a portion of said core member and providing access for pressure fluid beneath said sheet whereby the space under said sheet may be filled with compressed air and said sheet expanded radially outwardly upon one side of said core member; and a plurality of rigid interchangeable longitudinally aligned printing sleeves surrounding said core member and each having an internal cylindrical surface of the same curvature as said ground surface on said core member, each of said sleeves carrying one or more printing plates relating to a particular job to be run; all whereby introduction of compressed air beneath said sheet will cause the sheet to expand radially outwardly and firmly press approximately half of the internal surface of the sleeve against the ground surface of the core member.

References Cited in the file of this patent UNITED STATES PATENTS Kling Apr. 21, 1903 Grignard Dec. 17, 1912 Dixon et al Mar. 18, 1919 Eaglesfield Mar. 1, 1932 Nunnally' Apr. 6, 1943 Campbell Jan. 9, 1945 Barsam Nov. 11, 1947 Piperoux et a1. Jan. 22, 1952 Schoonberg Jan. 29, 1952 

